Chipotle shares, under siege after a series of food scares erupted just over a year ago, surged at the opening bell after activist investor Bill Ackman revealed that he's become the chain's second-largest investor.
Ackman's Pershing Square Capital Management LP has amassed a 9.9% stake in Chipotle Mexican Grill Inc., according to a filing with the Securities and Exchange Commission.
Shares jumped 5% in early trading Wednesday.
After taking a major stake, Ackman has in the past shaken up the leadership of ailing companies, and that is what Chipotle has become since the first outbreak of E. coli last year.
Shares that hit an all-time high close to $760 in...